chore: merge blocksuite source code (#9213)

blocksuite/affine/shared/src/utils/signal.ts

@@ -0,0 +1,25 @@
+import { signal } from '@preact/signals-core';
+
+interface Observable<T> {
+  subscribe(observer: (value: T) => void): Unsubscribable;
+}
+
+interface Unsubscribable {
+  unsubscribe(): void;
+}
+
+export function createSignalFromObservable<T>(
+  observable$: Observable<T>,
+  initValue: T
+) {
+  const newSignal = signal(initValue);
+  const subscription = observable$.subscribe(value => {
+    newSignal.value = value;
+  });
+  return {
+    signal: newSignal,
+    cleanup: () => subscription.unsubscribe(),
+  };
+}
+
+export { type Signal } from '@preact/signals-core';